Combination thread-tap.



A. S. SPINNEY.

COMBINATION THREAD TAP. APPLicATloN F1150 11011.19. 1911.

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f e 15, @w60 UNITED STATES PATENT @FFICEQ ALBERT S. SPINNIEY, OFPORTSMOUTH, NEW HAMPSHIRE, ASSIGNOR TO HARVEY KNIGHT, OF YORK COUNTY,MAINE.

COMBINATION THREAD-TAP.

Specification of Letters Patent.

Patented Oct. I5, 1918.

Application iiled November 19, 1917. Serial No. 202,889.

To all 'whom t may concern:

Be it known that I, ALBERT S. SPINNEY, a citizen of the United States,residing at Portsmouth, in the county of Rockingham and State of NewHampshire, have invented a new and useful Combination Thread-Tap, ofwhich the following is the specification.

This invention relates to the cutting of two or more di'erent threads inand by the same operation by means of a special tool or tap, so devisedthat a spring, or springs, furnishes the pressure necessary to start oneof the taps, and compensates for the difference in the leads. This hasas -its object the elimination of one or more operations, saving timeand energy.

I attain these objects by the mechanism illustrated in the accompanyingdrawing in which- Figure 1 is a longitudinal section through the work.

Fig. 2 is a view in side elevation of the combination thread tap.'

Fig. 3 is an end view of the tap.

Fig. 4 is a section lengthwise through the outer tap, the inner tapbeing shown in elevation. y

Fig. 5 is a cross section on the line A-B of Fig. 4.

Fig. 6 is a cross section on the line C-D of Fig. 4.

The combination thread tap consists of an outer tap (a) provided with alongitudinal bore (b) in which is seated the shank (d) of the inner tap(c). To prevent relative rotation between the taps, the shank (d) isprovided with longitudinal grooves (e) engaged by pins (h) projectinginwardly into the bore of the outer tap.v A pin (i) extends transverselythrough the outer tap and through an elongated slot in the shank (d).This pin allows for the diiferences in the lead of the two taps. Toprovide the necessary starting pressure for the inner tap, a spring (f)is interposed between the end of the shank (d) and a plug (g) threadedinto the end of the bore The described construction permits thesimultaneous cutting of two different threads in axially alined bores,the spring together with the pin and slot connection between the twotaps compensating for any difference in the lead of the taps.

I claim:

In a threading tool of the class described in combination, an outerthreading tool and an inner threading tool slidably mounted therein anda yieldable connection between said tools whereby differences in leadare compensated for, and pressure is furnished to start the innerthreading tool on its work.

ALBERT S. SPINNEY.

Copies of this patent may be obtained for live cents each, by addressingthe Commissioner of Patents,

Washington, IJ. C.

